Dwarf mondo grass (Ophiopogon japonicus) is a member of the lily family and thrives in warm temperatures (hardy to USDA zones 6a to 10b). Growing 2 to 4 inches in height, dwarf mondo grass is disease resistant and grows well in the shade, although it will tolerate full sun. The planting area for dwarf mondo grass needs to be free of weeds and weed seeds prior to planting, so begin preparing the area six weeks prior to putting your dwarf mondo grass in the ground.
Add 2 1/4 lbs. of 23-3-7 fertilizer per 1,000 square feet of planting area. Pour it onto the soil and mix it in well. This will encourage weed seed germination and growth.
Water the area every other day, until the soil is saturated, for two weeks. Do not water on any day that there is rain.
Apply a contact systemic herbicide to the weeds, at the rate suggested on the package. The weeds should die within one week, according to horticulturists with the University of Hawaii. Manually remove all dead weeds.
Add another application of fertilizer, at the same rate that you used the first time, and till it in to a depth of 5 to 6 inches. Add 3 inches of compost and mix that to the same depth. The fertilizer and compost should be completely incorporated into the soil. Rake the soil until it is level.
Water the planting area until the soil is saturated and continue to water to keep the soil moist for two weeks to allow any additional weeds to sprout.
Apply a second application of the herbicide, allow one week for the new weeds to die, and remove them from the planting area.
Remove the mondo grass from the nursery pot by tipping the pot on its side and sliding the plant out. If the plant is pot bound, give the bottom of the pot a sharp rap with your hand and it should slide out.
Separate the dwarf mondo grass into smaller clumps by breaking them or tearing them, with your hands, into individual clumps with roots and rhizomes.
Dig planting holes for the dwarf mondo grass that are the same depth and 1/2 inch wider than the root ball. Space the plants 6 inches apart if you are planting as ground cover. Place the roots of the dwarf mondo grass in the holes and pack the soil around the base of the plant.
Water the area until the top 4 inches of soil is damp, not soggy.
Apply a pre-emergent herbicide, labeled for use on mondo grass, at the rate listed on the packaging.